1. Field of the Invention
The present invention relates to sphygmomanometers or blood pressure measuring devices generally and particularly to sphygmomanometers having a locking mechanism which allows the cuff to be easily affixed around the limb of a body without shifting it thereon.
2. Description of the Prior Art
In the measurement of blood pressure, a sphygmomanometer assembly includes a cuff which is wrapped around the limb to thereby measure blood pressure. The cuff has a measuring area which must be accurately placed against the veins of the limb to produce an accurate measurement.
Known prior art cuffs were applied to the limb by placing one end of the cuff on the limb and then wrapping the other end around the limb to capture the first end. Difficulties occur in such a placement since the cuff tends to circumferentially shift around the limb due to the pulling action on the single opposite cuff end. When the cuff shifts, an inaccurate measurement occurs. An example of such prior art cuffs may be found in U.S. Pat. No. 3,765,405 issued to F. Natkanski.
Since the end of the cuff which is placed initially on the limb must be manually retained before it is captured by overlapping it with the opposite end, some bandages or cuffs utilize mechanical locking assemblies. In such assemblies a slotted buckle is affixed to one end of the cuff and the opposite end is threaded therethrough. The cuff is then tightened by pulling on the threaded end. An example of such locking assemblies may be found in U.S. Pat. Nos. 3,713,446 and 3,633,567 issued to S. J. Sarnoff. However, since the cuff is pulled at a single end the tendency to circumferentially move the cuff is still present and inaccurate measurements still occur. Such locking assemblies are also costly to manufacture and tend to break easily.